elm beautiful type annotation

elm-type-annotation-for-arguments-and-return-type.elm

module Scratch exposing (..)

import String


-- arguments first then return
-- so the arguments are wrapped in braces for disambiguation
-- http://guide.elm-lang.org/types/reading_types.html


twoIdentity : a -> a -> List a
twoIdentity a b =
    [ a, b ]


call : (a -> b) -> a -> b
call a b =
    (a b)


uppercase : String -> String
uppercase a =
    String.toUpper a



-- to try in `elm-repl`
-- import Scratch
-- Debug.log "call:" (Scratch.call Scratch.uppercase "foobar")